Solder Blamed for Faulty Window Operation

Our Honda Odyssey was hit in the driver-side door. Several months after receiving the vehicle back from the body shop, I noticed that the passenger-side window would go down whenever someone closed the driver-side rear window. The passenger window could then be subsequently closed. This never happened before the accident. We operated the windows like this for some time until I finally decided to try to solve the problem.

My initial thought was that some of the wires in the door had shorted together. I pulled the door panel and discovered that there was no damage, and they were all intact. I then pulled out the shop manual, studied the wiring diagrams, and learned that the driver’s window switch assembly was a local controller that sent control signals to window controllers under the dash and at the rear of the vehicle. While operating the windows as part of the troubleshooting process, I also learned that the rear window would close when the passenger window was opened from the driver’s door.

The easiest next step would have been to replace the driver-side switch assembly. This, of course, would not be nearly as much fun as figuring out why the windows did not work correctly. I inspected the window switch control board with a magnifying glass.

The leads from the four window switches are connected to the control board in a row of solder joints at the edge of the board. With the help of the magnifying glass, I found a tiny bridge of solder between two of the solder connections. The two connections were from the front passenger-side window switch and rear driver-side window switch! Now it all made perfect sense. I carefully removed the solder bridge with a knife, and the windows now work as they should.

This entry was submitted by Thomas W. Manning, Jr., PE, and edited by Rob Spiegel.

Tom Manning graduated from Drexel University in 1984 with a master's degree in mechanical engineering and began working in the field of machine vibration measurements in the engineering department of DuPont. In 1989, he began process equipment development work for the DuPont Lycra business at Benger Laboratory. He returned to DuPont Engineering in 2005 and now works to improve the quality, yield, and productivity of Nomex and Kevlar products.

honda's really trying their best to improve their designs but this still happens to a lot of people. have been looking here on some models (http://www.drivewire.com/make/honda/) and i think they are improving slowly, too.

"Idiots" was very kind... I would define them using other words! What is happening to the so called "design teams" in all the car manufacturers lately?

My wife has bought a new car (Volkswagen Jetta), that lacks the passenger side lock, so that the only way to enter the car is through the driver's side door. Evidently, the stupid designers have never been trapped in a parking lot in a too cramped space so that you have to enter the car on the other side.

To complicate things a little more, the economy version of this car lacks a remote (even when it has electric door locks), so that you have to open the driver's side door (the only one with a key hole), and then VERY QUICKLY introduce the key into the ignition and turn it to "ON", because the very "clever" designers programmed the damn alarm to sound off BEFORE 20 seconds or so... so that if you don't want to bother your neighbors, you have to be very agile in order to be able to open the lock, open the door, jump inside the vehicle, insert the key and turn it before the all too cautious 20 second period, unless you want to blast everyone with the claxon alarm! this is NOT a minor inconvenience, because if you are carrying a grocery bag or any other package, you must put it on the floor to be able to deactivate the damn alarm before it goes off... which compromises your own safety... how about that?

The very worst thing that the idiots have done, after switching to the multiplexed system, is to remove the key unlocking function from the passenger side door. How cheap can they get? Presently the only way to unlock the passenger side door from outside also unlocks all of the other doors. In the minivan that is four extra doors unlocked for very unsavory elements to yank open and remove items. Or to jump in and cause grief of various kinds. All this to save the cost of one lock cylinder, probably about $3 in production quantities. I would have been happy to pay $ 10 or even $20 to have that second lock as an extra option, but, instead, some fool decided that there was no need for it. JUst exactly what drove the idiot monkey to think that change was OK?

Absolutely! I have the same kind of problem with one of my two Dodges (guess which one), but I suspect this stupid vogue about (ab)using electronics for the most simple and strightforward tasks has gone too far. While my older car (1991) has perfectly operating electric door locks, those design geniuses decided to "save" some wire by multiplexing the door lock switches. Now the switch has only two wires...

I did a little research (google), and found this (somewhat faulted) explanation, probably written by a overly enthusiastic electronics designer:

"There are 2 resistors in the switch, a 620 ohm for unlock, 2700 ohm for lock and the switch is open at rest.

The switch toggles 12 volts between the 2 resistors.

The return wire goes the BCM (Body Control Module) to be interpreted as to what selected position the switch is in.

From there the BCM will power the door lock motors in the door latches to lock or unlock the doors. So basically the switch is '2 states plus off' (power in, difference out).

By multiplexing commands on 1 wire (sic), they probably saved 20-30 feet of wire per car on power door locks alone! This saves money, electrical complexity and weight..."

Ooh yeeeaah!!!

This extremely "brilliant" person forgot to say (and understand), that now the damn car NEEDS an overly complex, heavy and very costly to repair "Module", buried deep inside the left side of the dash. Since the damn module has reliability problems, many owners have discovered the trouble that the "magic" of electronics has created in this design, that means the affected owner now has to resort to a specialized repair center, where the module (no longer serviced by dealers) can be exchanged or repaired for around $400-500 USD not including the hassle of removing and reinstalling it. About 99% of the modules fail after 3 years and the failure is intermittent at first, so that most naive owners (like myself), just continued using the car, and then found the failure became more pronunced and permanent just after car warranty expired. By the way, Dodge Dealers knew about this, but kept pretending (faking would be more appropriate) that it was a "programming related fault", and that a simple DRB2 manipulation would correct the condition, which was a hoax of course... (The system allows the owner to re-program the door lock action through start key signaling, but the procedure can introduce more serious faults, requiring the tech to perform a much longer keystroking sequence and to request help from factory!)

Since the power locks are interfaced with the theft alarm and remote control, it is not as easy as simply rewiring the doors and changing the switch connections without losing functionality (at least on my car, the "open" command still works on the drivers side front door).

By contrast, my older Dodge still operates its door locks and windows after 21 years and many miles flawlessly. So much for "progress" and true quality.

As some of you, I love to repair broken things instead of replacing them, but the task of removing the Body Control Module means a heavy, extremely uncomfortable job (it is easy if you have the factory semi-robotic arm at home, which lifts the entire dash assembly and swings it into position inside an almost empty car shell, which is the way they do it at the plant!). Otherwise, you need to hire a dwarf with strong arms and some dexterity. I guess we need to teach the KISS principle to the newer generations of design geniuses, unless we want and can afford to replace the entire car at the first failure!

Ann, yes, it is true that my nomenclature was a bit dated. But still, the question stands as to why add some unreliable and cheaply produced electronics to provide a function that thirty years ago was handled very well by a pair of relays that usually outlasted the car? The current service part sells for a lot more than tose relays did, even after accounting for inflation. And I am certain that current automation could produce a product at least half as good for only a bit more. Besides that, those relays were probably built in the USA, and applicable to many models for a few years, reducing NRE costs a lot.

I had the same question as William: why are there so many different PCBs to control the windows? However, I'm not sure about your comment re MCUs, which have been around since the 60s and are usually referred to as "controllers," as they appear to be in this article. True, those older ones were very simple, low-end devices. Perhaps you mean they've gotten fancier than they need to be and the ones used here are unnecessarily complex and/or expensive?

I think you hit the important point on this, William. Questionable improvements may come with reliability problems. So the increased risk of failure due to increased complexity may not be justified. Additional cost just tips the scale that much more toward simple, reliable systems.

Why in the world does a car need multiple PC board assemblies to control the windows operation? That is certainly a case of feature-bloat, and clearly at the cost of reliability. Power windows functioned quite well enough in the 1960s, the application of microcontrollers does not provide benefits worthy of the increase in coasts and the reduction in reliability.

IT certainly did take some determined good trouble diagnostics to figure out where to look to fix the fault and repair the system.

You wouldn't believe what I have successfully repaired. When it comes to cars, the cost serves as effective motivator! All the repair needs to do is work, and fit mechanically where the original did (looking nice helps too). That being said, all cars have their problems. The best you can do is to buy the ones that hurt you the least on average.

All companies have a "corporate personality". That does not tend to change much over the years unless a company comes down with a fatal case of "bean counters". Then all bets are off!

I'm going to guess that you haven't actually driven a Saab. I have, and unless you have spent a few hours in a car driving over a large distance, you really don't know anything about it at all. Take care when reading reports from magasine writers though. That applies to most consumer products as well.

Back to the topic at hand though ...

I think Thomas did some excellent detective work and solved his problem rather than dinging Honda for it. There will always be isolated cases where extremely odd faults are found. Now, who's at fault here? Does it matter if it is an isolated case?

Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.